The Flow Cytometry Core provides flow cytometry research support for Center members. The Core endeavors to provide high quality multi-color analysis, high-speed sorting (including biohazard sorting), education, consultation, application development, and data analysis. The Core has changed dramatically since the 2003 review. Use has increased 50%. To accommodate and permit this increase the Core has increased both hardware and staff. We have added four analytical cytometers ~ three 9-color CyAns and an 18-color LSRII and two sorters ~ a digital MoFlo XDP and Reflection. The Reflection which is configured for BSL-2+ sorting has been placed in specially renovated BSL-2+ space. We have also upgraded the FACSCalibur and FACScan to dual-laser, 5-color instruments. We have added two highly skilled 1.00 FTE positions to accommodate the increased use and to provide additional services. Notably, the Core's staff has an aggregate of 77 years of flow cytometry experience. In sum the Facility provides state-of-the-art analytical and sorting flow cytometers, expertise, education, consultation, data analysis, and ease of access (domain and website, central data storage and archiving, web-based scheduling). The Flow Cytometry Core is directed by Dr. Larry Arnold, the Director since the inception of the Core In 1982. In 2009 152 laboratories used the Core; Center members accounted for 76% of total use. The CCSG budget request is for $141,810 representing a CCSG contribution of 23% to the total projected budget. The requested increase is to help establish the new biohazard sorting facility which for the first-time will permit sorting of viable human materials and other pathogen containing materials by Center members. Our future plans are to concentrate on education of users to increase their competency and, thus, data quality. Our single technology investment plan is to evaluate the utility of the Amnis ImageStream imaging flow cytometry technology for our users.